Electric arc furnaces steal show.In the Steel Division this year, the hot topic of discussion was how to better use electric arc furnaces. S.A. Hornby-Anderson, Walnut Creek, California Walnut Creek is a largely affluent suburb several miles east of Oakland in Contra Costa County, California, USA, in the East Bay region of the San Francisco Bay Area. While not as large as the neighboring Concord, Walnut Creek serves as the business and entertainment hub for the , and C.L. Bermel, Countryside, Illinois Countryside is a city in Cook County, Illinois, United States. The population was 5,991 at the 2000 census. Geography Countryside is located at (41.778885, -87.874006)GR1. , both of Liquid Air Corp., discussed the new technologies and benefits of electric arc furnace (EAF EAF - Effort Adjustment Factor ) bottom stirring. EAF bottom stirring has rapidly gained worldwide acceptance in large steel mills as a means to facilitate improvement in quality while reducing operating costs operating costs npl → gastos mpl operacionales . The technology was designed to overcome concentration and temperature gradients as well as over-oxidized slags. Today's EAF stirring is practiced using directional porosity plugs, multi-hole plugs or porous elements installed at the EAF bottom. Current techniques make it much more cost-efficient and practical than earlier models. According to according to prep. 1. As stated or indicated by; on the authority of: according to historians. 2. In keeping with: according to instructions. 3. the authors, steel mills and foundries have found EAF bottom stirring reduces energy consumption, tap-to-tap time, operating costs and refining times while increasing productivity and yield. Bottom stirring also contributes to lower electrode and refractory wear as well as nitrogen pickup when using argon argon (är`gŏn) [Gr.,=inert], gaseous chemical element; symbol Ar; at. no. 18; at. wt. 39.948; m.p. −189.2°C;; b.p. −185.7°C;; density 1.784 grams per liter at STP; valence 0. gas. The authors evaluated costs for a 30-ton EAF bottom stirring installation. They concluded that it could save $113,900 a year and noted that the technology offers similar cost-saving benefits for foundries with smaller EAFs. C.F. Pilliod, Keokuk Steel Casting Div., Keokuk, Iowa, discussed the variables controlling nitrogen content of steels produced in electric arc furnaces. He explained that excessive nitrogen contents in steel causes gas porosity and aluminum nitride embrittlement Embrittlement A general set of phenomena whereby materials suffer a marked decrease in their ability to deform (loss of ductility) or in their ability to absorb energy during fracture (loss of toughness), with little change in other mechanical properties, such . Under normal conditions, gas porosity can be detected and repaired, but aluminum nitride embrittlement is virtually impossible to detect on a production basis in foundries. To produce steel with minimum nitrogen levels, Pilliod suggested purchasing melting scrap with low nitrogen contents, using charge with adequate silicon, carbon-boiling, lowering voltage taps and recarburizing the bath. Each of these steps, he said, reduces nitrogen content. To help control nitrogen and oxygen that can be introduced during melting, D. Lawrenz, LECO Corp., St. Joseph, Michigan St. Joseph is a city in the U.S. state of Michigan. As of the 2000 census, the city population was 8,789. It lies on the shore of Lake Michigan, at the mouth of the St. Joseph River, about 60 miles due east of Chicago. It is the county seat of Berrien County6. St. , offered attendees an introduction to modern gas fusion oxygen and nitrogen instruments. He said many instruments provide precise oxygen and nitrogen determination in a variety of materials in less than a minute. Advanced capability determinators offer controlled fusion and separation of the oxygen and nitrogen as they are released from a sample, allowing users to quantify existing oxide and nitride bonds. |
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